Understanding dual-band wi-fi routers

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Most routers these days are dual-band, offering both 2.4GHz and 5GHz wi-fi networking. But what's the difference? What does it mean?

Without getting too bogged down in the various wireless networking standards, broadly, the two bands are those two frequencies, with the lower-frequency 2.4GHz offering a longer reach, and the more modern and higher frequency 5GHz being able to move more data around faster.

So which band should I use?

It depends what you want to do. If you’re watching the iPlayer or other streaming service such as Netflix on your tablet, or playing games on a console, you’ll have a much better experience doing so on the 5GHz band. That’s because it can transmit much higher amounts of data, and so your movie or game won’t suffer from excessive buffering (when the picture or game slows down or stops as it waits for the video to catch up) or drop out.

If you’re just browsing the web, you’ll be fine on the older 2.4GHz band because browsing uses less data.

What are the downsides?

As mentioned above, the 2.4GHz band is slower: it’s less able to handle the high throughput of streaming video. However, the 5GHz band won’t reach as far: if you want to watch the iPlayer at the bottom of the garden, you’re probably going to be restricted to the slower 2.4GHz band as the 5GHz has a shorter range.

Another downside of 2.4GHz is that it’s a crowded: not only will many of your neighbours be sharing it, a lot of other wireless devices are on that frequency too, such as cordless phones and baby monitors. The 5GHz bandwidth is less likely to suffer from interference.

What about security? Should I give the different bands a different password?

There’s no need from a security point of view to give the two bands a separate password. So long as you’ve got a strong password for your network, you can use the same one for the 2.4GHz band and the 5GHz band. The only reason you might want to have separate passwords is so that you can make sure other people are on the band most suitable for what they’re doing. So if you’ve got the grandchildren round and they’re playing a game, you could make sure they only connect to the 5GHz band so that you can get on with your browsing without them hogging all the bandwidth while they kill zombies.

Will my phone and tablet switch automatically between the bands?

It depends on your device. Older devices might not be able to connect to the newer 5GHz band at all, while others will flip seamlessly between them.

That’s not always a good thing, though: most devices will pick the stronger network, regardless of what’s better for what you’re doing. So if you’re watching a film on your phone and move away from the router, it might switch from 5GHz to 2.4GHz without warning, and you’ll only know when the film starts buffering and stuttering. If you need to stay on one band, tell your phone to ‘forget’ the other, and connect back to that manually later when you need to.